1. Field of the Invention
This invention pertains to a humidity regulating unit and to a method of manufacturing a humidity regulating unit.
2. Description of the Related Art
Japanese Unexamined Patent Appl. No. 62-26076 discloses a humidity regulating unit in which a tube is used to carry water over a heating element. The tube has a porous retaining wall as the main wall through which water does not pass but steam passes. This humidity regulating unit is designed such that an electric heating element (with a diameter of at least 3 mm) is arranged inside the tube by preparing one tube with a somewhat large diameter. During use, this water carrying tube is connected to a water supply source such that the tube is always filled with water. Steam is expelled through the porous retaining wall of the water carrying tube by the heat of the electric heating element.
When this type of humidity regulating unit is used inside the inhalation route (inhalation circuit) of an artificial respirator, for example, not only can it assure humidifying performance, but using the fact that the outer shape of the humidity regulating unit is a tube, the humidity regulating unit can be arranged in the inhalation route and does not require a large-volume chamber for a humidifier.
However, in the humidity regulating unit described above, from considerations such as assuring adequate steam generation and the size of the heating element, a water carrying tube that has a somewhat large diameter must be used. If the water carrying tube is broken, an impermissible amount of water inevitably leaks which can cause various problems. When the humidity regulating unit is used in the inhalation route of an artificial respirator, for example, water leakage has the undesirable effect of reducing humidifying performance and the leaking water itself can flow to the inhalation side of the inhalation circuit, which is the side where the user of the artificial respirator is located.